1. Field of the Invention
The present invention relates to a hand-held setting tool including an actuation switch, connection means for connecting the setting tool to a positioning device and having a counter-coupling element for the positioning device, a structural component, and a mechanical switching link including at least one first switching element displaceable in the structural component along an axis of the setting tool for connecting an actuation element provided on the positioning device with the actuation switch, and a safety device for preventing actuation of the actuation switch of the setting tool at an orientation of the setting tool other than a predetermined orientation.
2. Description of the Prior Art
Positioning tools of the type described above are used, e.g., at overhead works in case of high ceilings when working is possible only using working platforms or ladders. Setting tools, which can be used with such devices, can be driven with solid, gaseous, or liquid fuels or with compressed air or electricity.
U.S. Pat. No. 4,479,599 discloses a positioning and actuation device for a combustion-operated setting tool and including connection means for the setting tool, which is arranged at an end of an elongated holder and is formed as a rod or a bar. The rod or bar is axially displaceable relative to the connection means for actuating the actuation switch of the setting tool that is secured at the connection means via coupling means. For actuating the setting tool, the tool should be placed with its muzzle part against a ceiling and then be displaced in the direction of the ceiling with the holder or rod by the user.
Further, the positioning and actuation device has a safety device which prevents the setting tool from being actuated when the muzzle part is oriented exactly in the direction of the force of gravity. For this purpose, the safety device has a blocking member formed as a ball which is guided in a recess formed as a channel and extending in the connection means diagonally to the longitudinal axis of the rod. At an orientation of the tool in the direction of the gravitational force, the ball rolls into the movement path of the rod and prevents a further movement of the rod relative to the connection means and, therefore, prevents actuation of the setting tool secured on the connection means. To this end, the rod has, at its end adjacent to the connection means, a radially circumferential recess into which the ball can fall.
The drawback here consists in that the actuation of the setting tool can only be safely prevented when the positioning and actuation device with the setting tool is oriented exactly with the muzzle part facing in the direction of the force of gravity.
U.S. Pat. No. 7,014,085 discloses an explosion-actuated setting tool having a housing, an elongated holder projecting therefrom, and a ball-controlled safety locking device which permits the setting tool to be actuated only in a vertical or almost vertical orientation opposite to the force of gravity. The ball of the ball-controlled device is arranged in an annular receiving space between the holder and the housing.
However, the drawback of the setting tool of U.S. Pat. No. 7,014,085 consists in that the diameter of the ball defines the maximum movement path of the holder relative to the housing which is available in the release position of the ball and within which all of the necessary functions such as, e.g., initiating of ignition, must be carried out. Therefore, a very high pressing force is needed for this short movement path.
Another disadvantage consists in that widely different angles result when the setting tool is lifted upward until released, and when the setting tool is lowered until blocked again; that is, the limiting angle at which a setting process is still possible when the setting tool deviates from a vertical orientation opposite to gravitational force can vary dependent on the changes in orientation of the setting tool prior to actuation. Moreover, when the setting tool is pressed horizontally against a wall or downwardly against a floor by moving the tool up or down, the blocking ball rolls out of its blocking position, and the setting tool becomes inadvertently released.